Method of producing tubular members



Dec. 26, 1944. P. s. HAUTON METHOD OF PRODUCING TUBULARMEMBERS 2 Sheets-Sheet 1 IN VEN TOR.

1 4212 51522! Zwz Y Filed Nov. 29, 1941 Dec, 26, 1944. v P. s. HAUTON METHOD OF PRODUCING TUBULAR MEMBERS 2 Sheets-Sheet 2 Filed Nov. 29, 1941 IN VEA TOR 212 ,5 22am Z022 3 TT RNEY Patented Dec. 26, 1944 METHOD OF PRODUCING TUBULAR MEMBERS Paul S. Hauton, Atlanta, Ga., assignor to Scripto Manufacturing Company, Atlanta, Ga., acorporation of Georgia Application November 29, 1941, Serial No. 420,925

4 Claims.

This invention relates to the method of forming coiled tubular members from flat stock and more especially to the method of forming coiled tubular members having spaced turns for use as a threaded member in mechanical pencils.

One of the objects of the invention is to provide means for efiiciently and efiectively coiling a flat strip of material into spiral form to produce a tubular member. 7 1

Another object of the invention is 'to provide a more accurate and efiicient threadedmember for mechanical pencils and for producing such threaded member efilciently.

Other-and further objects will be pointed out or willbecome apparent to one skilled in the art as the description proceeds.

Ccmprehensively stated, the invention comprises pushing a preformed flat strip or blank of material into a coiling device so that the flat blank is coiled to form a tubular member.

More specificallystated.theinvention comprises first forming a flat blank from suitable stock to requisite dimensions and shape, then positioning one end of the generally elongated blank so that its end is initially confined in a forming device and pushing or force-feeding the blank in a lengthwise direction at an angle to the members of the forming device more especially by pushing against the end remote from the forming device and progressively confining by the forming members successive portions thereof during the advance of the blank so that the successive portions coil to form the tubular member.

While one embodiment of this invention is illustrated in the accompanying drawings, it is to be understood that such embodiment merely serves as an illustration of the underlying principles of the invention so that it may be readily comprehended by those skilled in the art, and is not intended as limiting the invention to the specific details disclosed therein.

In said drawings:

Fig. 1 is a transverse section of the means for forming the coiled strip ortubular member showing the coil in the process of formation.

Fig. 2 is a fragmentary elevation of a preformed blank cut to desired shape and length andhaving an opening cut therein.

Fig. 3 is a fragmentary elevation of the finished coil.

Fig. 4 is a section of Fig. 2 onth lline 4-4.

Fig. 5 is a section of Fig. 3 on the line 55.

Fig. 6 is a view similar to that shown in Fig. 1

with the fiat strip converted to a coiled strip.

Fig. 7 is a fragmentary view of some of the ing mechanism.

elements shown in Fig. 6 showing the mechanism for ejecting the finished coil from the coil form- Fig. 8 is a section of Fig. 6 on the line 88.

Fig. 9 is a section of Fig. 6 on the line 9-9.

Continuing now by way of a more detailed description, the blank A is stamped or punched from suitable stock to form an opening B at one end of the blank and also to form the two opposite bevelled edges C and the taper D and bevelled edge E at the end of the blank opposite from th opening B. The purpose of the opening, the bevelled edges and taper D is to form a threaded tubular member more especially adapted for use in the mechanical pencil disclosed in the copending application of Paul S. Hauton, Serial No. 259,535, filed March 3, 1939.- While specifically the product resulting from the method herein disclosed is more especially applicable for use in a mechanical pencil, the present process is also applicable to the formation of other types of tubular members and including tubular members having the edges of the coiled turns abutting. In order to coil the preformed blank A to form the coiled spiral having spaced turns as shown in Fig. 3, the-blank A is pushed through a suitable device whlch comprises a block F having an opening or bore G of a diameter substantially corresponding to the outside diameter of'the finished coil as shown in Fig. 3. Concentrically located in theopening G there is a stationary cylindrical spindle or mandrel H of a diameter corresponding approximately to the inside diameter of the finished coil shown in Fig. 3. The relation between the diameter of the mandrel H and the bore G is proportioned to the stock used and dimensioned to provide clearance between the mandrel H and the wall of the bore G substantiallycorresponding to the thickness of the stock so that as one end of the blank hereinafter designated the front end is pushed into position against the arcuate wall of bore G, it is forced to coil around the cylindrical mandrel H coaxially located therein. The mandrel H in addition to serving in conjunction with the opening or bore G as a former for the coil projects beyond the block F so as to serve as a guide for the coil when the latter in its finished form is pushed along the mandrel for ejection fromthe block F. The block F having the bore G with its coaxially disposed mandrel H has a blank guide channel or guide K with its longitudinal axis angularly disposed with respect to th axis of the bore and having one and communicating with the forming opening so that one end of the blank is initially confined between-the forming opening and the mandrel when the blank is moved to its initial position. The channel may be and preferably is extended or continued through an auxiliary block F fitted to the main block F so as to form an extension of the main block and to aiford the requisite length of channel K which may be and preferably is approximately the same as that of the blank A. While in the specific embodiment a main and auxiliary block are shown and described the auxiliary or separate block is used for ease of construction. The channel K is closed oil by a cover P with the shape of the channel proper corresponding closely to the width and thickness of blank A so that the latter may slide freely lengthwise in the covered channel and yet have the necessary support against buckling when pressure is applied to the blank to advance it through the former durin the coiling operation. A pusher member L having a cross sectional dimension corresponding to the cross sectional dimension of the blank has a pusher nose L' adapted to push against one end of the blank when the latter is located in'the channel. In order to'make the pusher more rigid it has a longitudinally disposed dependent web M adapted to ride in a guide slot N formed in the guide block F and its auxiliary block F contiguous to and merging with the blank guide slot K. The end of the dependent web M terminates short of the pusher nose Lf so that the latter may be advanced sufliciently so that the blank may be completely acted upon by the forming members. 0n the angular relation of the direction of feed of the blank feeding slot K to the axis of the mandrel and its concentric bore and the width of the blank will depend the spacing of the turns of the tubular member. When the pusher plate L has reached the end of its forward stroke as shown in Fig. 6 it may be retracted so as to aiTord clearance for the movement of a sleeve R surrounding the mandrel H and sliding in bore G. This sleeve is moved toward the pointed end J of the mandrel H so that the finished product will be partly supported by the projecting end of the mandrel as abovejndicated from which it can conveniently be removed either by hand or suitable mechanism. Suitable mechanism (not shown) if desired may be used to operate the pusher plate L and to operate the ejector sleeve R although obviously these parts might be manually operated particularly when the finished coil is of the comparatively light stock customarily and mandrel. As the forward movement of the pusher member L is continued the successive portions of the blank are confined and constrained to coil around the mandrel until the pusher'element reaches the end of its stroke. On retracting the pusher element L the sleeve R may be moved toward the pointed end of the stationary mandrel H and the finished product ejected so that the process may be repeated with a new blank.

In carrying out the series of steps which result in the tubular member, the preformed blank is confined in a guide channel and positioned with one end initially confined between the form ing elements. The preformed blank is then advanced by exerting pressure'at some point where used for forming the helix in a mechanical pencil.

. the guide channel; the pusher plate L with its dependent web M is moved in the direction of the arrow shown in Fig. 1. This pushes the end of the blank between the mandrel H and the wall of bore G and initially confines it. By continuing the movement of the pusher plate L in the direction of the arrow against the back end of the blank A, the front end is forced to coil by reason of the shape of the bore G and take a position at an angle to the direction of feed of the blank because of the angular inclination of the direction ofieed-with respect to the axis of the bore the blank is not-confined between the forming elements, the direction of advance bein at a predetermined angle to the axis of the'forming elements to confine successive portions of the blank forcing them to move in a curvilinear direction and at an angle so that successive coil turns are formed.

It is claimed:

1. The method of producing a helical coil from a preformed elongated blank, comprising, pushing said blank by applying force against the extreme rear end thereof by a reciprocating plunger, through a slot which entersthe cylindrical bore of a coiling die tangentially and at the proper angle in relation to the longitudinal axis of said bore to produce the desired helical angle, until the rear end of said blank is entirely located within the cylindrical bore, withdrawing the plunger from the cylindrical bore, pushing the coiled blank from the cylindrical bore by applying force against the rear end of the coiled blank through a reciprocating plunger which moves parallel to the longitudinal axis of the cylindrical bore, then withdrawing said reciprocating plunger from that part of the cylindrical bore which is occupied by saidblank during the coiling operation.

2. The method of producing a helical coil with constant helical angle and a helical space of uniform width between adjacent convolutions of said coil, from a preformed elongated blank. comprising, providing a rectilinear channel at least as long as said blank, sized to confine said blank laterally on all sides, and debouching tangentially into an annular channel obliquely related to said rectilinear channel at such an angle as to produce a helical space between adjacent convolutions of said coil as formed within said annular channel, the latter being of such uniform width as to confine said blank on opposite sides. inserting a' blank wholly within said rectilinear channel, pushing said blank through said rectilinear channel and wholly within said annular channel by force applied to the end of said blank solely in the direction of movement of said blank through said rectilinear channel, discontinuing said force, and pushing the spirally formed coil through and from said annular channel by force applied in the direction of the axis of said channel.

3. The method of producing a helical coil independently of the production of subsequent helical coils, from a preformed elongated blank having a rear end face terminating in a line substantially perpendicular to its length,'in a coiling die having a cylindrical bore and a slot' entering the side of said bore tangentially thereto, comprising, pushing said blank through said slot by force applied solelyto its rear end in a direction perpendicular to saidend and at an angle to the axis of said bore until said blank is located entirely within said bore but with its rear end not coiled, discontinuing said force, then prior to the entry of another blank into said bore, applying a force to the rear end of said blank within said bore in a direction of the axis of said bore to complete the coiling of said blank and to eject it from said bore.

4. The method of producing a helical coil independently of the production of subsequent helical coils, from a preformed elongated blank having a rear end shaped for applying a coiling force and an ejecting force, in a coiling die having a cylindrical bore and a. slot entering the side of said bore tangentially thereto, comprisiing, pushing said blank through said slot by a 7 force, applied to its rear end until said blank is located entirely within said bore, discontinuing said force, then prior to the entry of another blank into said bore, applying a second force to the rear end of said blank within said bore, said PAUL S. HAUTON. 

